We report the observation of electroluminescence from the first to fourth quantum wells (QWs) from the <i>p</i>-GaN layer in InGaN/GaN multiple-QW light-emitting diodes (LEDs) with various indium contents (4%–16%) in each QW. The investigated LED sample showed a lower turn-on voltage and ideality factor as well as a reduction of etching pit density compared with the reference sample. Also, the X-ray reciprocal space maps revealed a partial strain relaxation in the active region. The enhanced hole injection efficiency was attributed to the weakening of strain-induced polarization field in the QWs and the good crystalline quality.
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